JPH03246018A - Manufacture of platelike matter - Google Patents

Abstract

PURPOSE:To obtain a platelike matter whose facial accuracy is excellent, by specifying the diameter of a gate of the platelike matter and making only the inside of the platelike matter a foamed layer. CONSTITUTION:In an injection molding to manufacture a platelike matter, 1 and 1' are fitting plates of molds and 2 is a thin press plate, in the molds to be used. Then 3 and 3' are hydraulic cylinders for pressing action of a thin matter and 4 and 4' are a guide pin and a support pin of a press plate of the thin matter. Further, 5 is a rocket ring and 6 is a spray. Then 7 is a thin matter possessing a metallic layer. In addition, the diameter of the gate is made 6-30mm. When the diameter of the gate is less than 6mm, simultaneously with worsening of flowability also a valve of a facial accuracy index of the platelike matter becomes high. On the one hand, when the diameter exceeds 30mm, a hollow in the gate part of the platelike matter becomes large and it is not favorable from a view point of an external appearance. Further, since a foamed layer is formed within the platelike matter, the facial accuracy is improved and the hollow of the gate becomes unattractive.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a dish-shaped article with excellent surface accuracy. More specifically, when manufacturing a thermoplastic resin dish-shaped article laminated with a thin-walled article having a metal layer by an insert injection molding method, the gate diameter of the dish-shaped article is set to 6 to 3.
0 m+*, and furthermore, only the inside of the dish-shaped object is made of a foam layer to obtain an object with excellent surface precision.

[Prior Art] Currently, dish-shaped molded products such as parabolic antennas are being manufactured. This parabolic antenna must be made of metal or have a metal layer on its surface to reflect radio waves from satellite broadcasting. For this purpose, metal plates are commercially available as parabolic antennas. However, since metals corrode, anti-corrosion alloys or anti-corrosive coatings are used. If anti-corrosion alloys are used for this purpose, they will be expensive. On the other hand, even with anti-corrosion coatings, it is necessary to repeat the coating several times to achieve complete corrosion protection, which not only makes them expensive, but also causes the problem of the coated items deteriorating over many years of use. be. Moreover, even if a parabolic antenna made of a metal plate having a predetermined shape is manufactured, so-called springback occurs after manufacturing, making it impossible to achieve the surface accuracy that is most important for a parabolic antenna.

Furthermore, have there been any attempts to manufacture a radio wave reflecting plate in which a thermosetting resin such as an unsaturated polyester resin is laminated with glass fiber or carbon fiber whose surface is metalized as a radio wave reflecting layer? 174
No. 95), the manufacturing method is complicated, and it is very difficult to maintain the radio wave reflective layer at a constant thickness and without unevenness, and furthermore, the radio wave reflection properties are poor. In addition, a parabolic antenna has been proposed in which an aluminum plate is used as a radio wave reflection layer and an olefin resin containing glass mat is formed as a base layer by compression molding. It is difficult to insert mold bosses etc.

Based on these facts, the present inventors have conducted various searches to obtain a reflector for circularly polarized antennas that has a simple manufacturing process, has radio wave reflecting ability, and can maintain its performance for a long period of time. , at least (^) a thermoplastic resin layer or coating layer with good weather resistance (B) a metal layer and (C) a thermoplastic resin layer containing an inorganic filler are laminated in sequence, and the thermoplastic resin The thickness of the layer or coating layer is 5- to 5 m+s, the thickness of the metal layer is 5 um to 1 am, and the thickness of the inorganic filler-containing thermoplastic resin layer is 500- to 15+o+.
w, and the content of the inorganic filler in this layer is 10 to 80% by weight.
We discovered that parabolic antennas (parabolic antennas) not only have excellent durability, but also have good radio wave reflection characteristics, and that they also exhibit various effects, and we have previously proposed them (for example, in JP-A-60-153202 and JP-A-60-153202). GO-153203, GO-153609,
No. 80-153610, No. 80-160207, No. 60-167503, No. 60-171801, No. 6
No. 0-171803, No. 60171805, No. 80-
No. 187107, No. 60-203005, GO-2
No. 12005, No. 60-235501-9).

Furthermore, the present inventors have proposed a method of manufacturing a plate-shaped object by the following method as a highly functional 1 (II-shaped object) by improving the surface precision by insert injection molding (Japanese Patent Application No. No. 9064).

[When manufacturing a thin-walled or laminated thermoplastic resin plate having at least a metal layer on its surface by insert injection molding, the cross section of the plate is defined by a parabola, and the surface of the plate is defined by a parabola. In molding a dish-shaped object in which a continuous line of parabolas is expressed by a general curved surface formula, the gate diameter is set to 6 to 2.
A method for manufacturing a plate-shaped object, characterized by forming a plate-like object into five parts. ” [Problem to be solved by the invention] However, Japanese Patent Application Laid-open No. 60-153202,
When a parabolic antenna is manufactured by the insert injection molding method described in publications such as No. 203,
The area coverage, which is the most important characteristic of a parabolic antenna, is not always satisfactory.

Furthermore, the invention described in Japanese Patent Application No. 1-9084 has a problem in terms of surface accuracy.

In light of the above, the present invention does not have these problems (defects), and uses the insert injection molding method to produce a dish-shaped object (for example, a parabolic antenna) made of a thermoplastic resin or a composition thereof laminated with a thin object having a metal layer. The objective is to improve the surface precision and obtain a highly functional dish-shaped object.

[Means and effects for solving the problems] According to the present invention, these problems are solved by manufacturing a thermoplastic resin dish-shaped object laminated with a thin-walled object having at least a metal layer on the surface by an insert injection molding method. Then, the cross section of the dish is defined by a parabola,
In the molding of a dish-like object whose surface is represented by a continuous line of the parabola in the form of a general curved surface, the gate diameter is set to 6 to 3 degrees.
The problem can be solved by a method for manufacturing a dish-shaped article, characterized in that only the inside of the dish-shaped article is made of a foam layer. The present invention will be explained in detail below.

(A) Thin-walled article The thin-walled article used in the present invention has a small number of metal layers.

(1) Metal layer Representative examples of metals that are raw materials for the metal layer in the present invention include simple metals such as aluminum, iron, nickel, copper, and zinc, and alloys containing these metals as main components (for example, stainless steel , brass). These metals do not need to be surface-treated, and may be previously subjected to surface treatment such as chemical treatment or plating treatment. Furthermore, those that have been painted or printed can also be preferably used. The thickness of this metal layer is generally from 5 μs to 1 m11, preferably from 5 to 500 mm, particularly preferably from 10 to 500 mm. If the thickness of the metal layer is less than 5 mm, the metal layer is likely to wrinkle or fold when producing a laminate, causing problems in terms of appearance and performance. On the other hand, if it exceeds 1 m+*, not only will the weight increase, but the cost will also increase, and problems will arise when the laminate is curved or bent.

In manufacturing the thin-walled article of the present invention, one consisting only of this metal layer may be used. However, when the resulting dish-shaped object is used for a parabolic antenna, the metal corrodes as it is used for a long time. Therefore, on the surface of the metal layer, a thermoplastic resin with excellent weather resistance [hereinafter referred to as "thermoplastic resin (I
)" may be formed on the coating film or may be laminated.

(2) Thermoplastic resin (1) The thermoplastic resin (1) is widely produced industrially and used in many fields, and its molecular weight varies depending on the type, but generally ranges from 10,000 to 1,000,000. It is. Among the thermoplastic resins (1), fluorine-containing resins such as polyvinylidene fluoride are desirable because of their excellent weather resistance. Furthermore, even with vinyl chloride-based resins, ethylene and/or propylene-based resins, the weather resistance of these formulations can be improved by adding UV absorbers. You can use it as you like. Furthermore, polyamide resins, polyester resins and polycarbonate resins can also be used. Among these thermoplastic resins (I), organic compounds having at least one double bond in the olefin resin (ethylene homopolymer, propylene homopolymer, copolymer mainly composed of ethylene and/or propylene) It is advantageous to use part or all of a modified resin obtained by graft polymerization of unsaturated carboxylic acids and their anhydrides (particularly preferred are unsaturated carboxylic acids and their anhydrides) because of their excellent adhesion to the metals described below. Regarding other thermoplastic resins (1), see JP-A-60-153202;
It is described in detail in the specifications of No. 60-153809 and No. 60-153810.

(3) Paint Paints used to form paint layers are widely produced industrially and used in a wide range of fields. Paints are classified into solvent-based, aqueous emulsion-based, and solvent-free, but any type can be used. Among the paints, polyurethane resin paints, acrylic resin paints, epoxy resin paints, aminoalkyd resin paints, and vinylidene fluoride resin paints are preferred because of their excellent weather resistance. Particularly, by incorporating an antioxidant and an ultraviolet absorber into the paint of the present invention, a paint with good weather resistance can be obtained, which is suitable. These paints are described in detail in JP-A-60-153203.

(4) Production of thin-walled products The thin-walled products of the present invention may be made of a metal layer as described above, but they may also be ones whose surfaces are laminated with a thermoplastic resin (I) layer or a coating layer with excellent weather resistance. If the adhesion between the metal layer and the thermoplastic resin (I) layer or coating layer is good, it is sufficient to make them stick together as is, but if the adhesion is poor, a so-called primer is interposed between them to make them stick together. It's okay. In addition, if the adhesion between the thermoplastic resin to be injection molded and the metal layer is poor, as described below, a brimer may be applied in advance to the surface of the metal layer where the metal layer and the thermoplastic resin to be injection molded are in close contact. . Alternatively, a thin material (film, sheet) that can be easily heat-welded to the thermoplastic resin to be injection molded may be attached. The types of these brimers vary depending on the thermoplastic resin (1) of the thermoplastic resin with excellent weather resistance, the thermoplastic resin to be injection molded, and the type of paint for the coating layer with excellent weather resistance. You can use commonly used brimers.

Even when laminating the thermoplastic resin (1) with excellent weather resistance on the metal layer, or when applying a coating material with excellent weather resistance, a commonly used method may be applied. Furthermore, the same applies when applying a brimer.

The thickness of both the thermoplastic resin (I) layer with excellent weather resistance and the coating layer is usually 5 mm to 2 mm, preferably 10 mm to 0.5 mm. In addition, when using a brimer, the thickness is generally 0.1 mm to 1 mm, especially 0.2 mm to 0.5 mm.
is desirable.

(B) Thermoplastic resin (II) In addition, the thermoplastic resin (II) to be injection molded in the present invention
Typical examples of I) include acrylonitrile-butadiene terpolymer resin (ABS resin) obtained by graft copolymerizing acrylonitrile and styrene onto propylene resin (PP), butadiene rubber, acrylonitrile-butadiene rubber, or styrene-butadiene rubber. ), ternary copolymer resin (AC3 resin) obtained by graft copolymerizing acrylonitrile and styrene onto chlorinated polyethylene, polyphenylene oxide resin (PPO resin), polyethylene terephthalate (PE
T), polybutylene terephthalate (PBT) and polycarbonate resin (PC resin). These thermoplastic resins are widely produced industrially and used in a wide variety of fields, and their manufacturing methods and various physical properties are well known.
For example, the Encyclopedia of Polymer Science and Technology
ia of' Polymer 5science and
Technology) Interscience Publishing (
Interscience Publisher, A
division or John Wiley &
5ons, Inc.), 1964-1971
Published in 2017].

The molecular weight of these thermoplastic resins varies depending on the type, but is generally from 10,000 to 1,000,000. The structure, manufacturing method, physical properties, etc. of these thermoplastic resins are disclosed in Japanese Patent Application Laid-Open No. 60-15
No. 3203, No. 60-171801, No. 601718
No. 03, No. 60-173902, No. 60-18710
No. 7, No. 60-206205, No. 60-210009
No. 80-235501, No. 60-235504, and No. 60-246106.

These thermoplastic resins (II) alone may be injection molded, but a composition obtained by adding an inorganic filler to the thermoplastic resin (II) may also be injection molded.

The inorganic filler is one that does not decompose during mixing and injection molding for producing the composition.

Inorganic fillers include metals such as aluminum, copper, iron, lead and nickel, oxides of these metals and metals such as magnesium, calcium, barium, zinc, zirconium, molybdenum, silicon, antimony, titanium, and their hydrates. Examples include compounds such as hydroxides, sulfates, carbonates, silicates, double salts thereof, and mixtures thereof. Among these inorganic fillers, those in powder form preferably have a diameter of 1 liter or less (preferably 0.51 liter or less). In addition, fibrous materials have a diameter of 1 to 50 mm.
0 ttm (preferably 1 to 300 mm) and a length of 0.1 to 6II11 (preferably 0.1 to 5 mm). Furthermore, the flat plate-like fillers have a diameter of 2 mm or less (preferably 1 μm or less).These inorganic fillers are generally widely used in the decomposition of synthetic resins and rubber, and are representative An example is the above-mentioned Japanese Patent Application Publication No. 80-15
It is described in various specifications such as No. 3202 and No. 60-153203.

When used as a composition in which the thermoplastic resin (n) is blended with an inorganic filler, the composition ratio of the inorganic filler in the composition is at most 80% by weight, preferably 75% by weight or less, particularly 70% by weight. % or less is suitable. Even if an attempt is made to produce a composition in which the composition ratio of inorganic filler exceeds 80% by weight, it is difficult to obtain a uniform composition, and even if a uniform composition is obtained, It is not possible to obtain a good product when manufacturing a dish-shaped object by injection molding, which will be described later.

(C) Manufacture of dish-shaped object In manufacturing the dish-shaped object of the present invention, first, the thin-walled object is set in advance on the moving side of an injection mold, and the thin-walled object is fixed at the outer edge of the mold. .

There are various methods for fixing, but generally it is fixed by hydraulic pressure. A position closer to the outer edge is preferred for fixing. Generally within a distance of 10cn+ from the outer edge,
1 to 30 mm is preferred, particularly 1 to 25 mm. If you fix the position farther than 1OcIn from the outer edge,
Metal layers may be cut or wrinkled in thin-walled objects. Further, it is preferable to fix the entire surface.

Then close the mold. Thereafter, the thermoplastic resin (II) or the thermoplastic resin (II) containing an inorganic filler is filled into the mold from the gate part of the mold, and after cooling, the mold is opened to form a desired dish. (for example, a parabolic antenna). In this case, the injection molding temperature is higher than the melting point of the thermoplastic resin (II) used, but lower than the thermal decomposition temperature of the thermoplastic phase m (II). Therefore, the molding temperature varies depending on the type of thermoplastic resin (II) used. The range of molding temperatures for typical thermoplastic resin (II) is shown below.

Type Molding temperature range PP 170-290ABS resin
200-290 AC5 resin 160-240 PPO resin 220-300 P C250-300 ('C) In addition, if the injection pressure is 40 kg/c- or more at the gauge pressure at the nozzle part of the cylinder of the injection molding machine, it is a thermoplastic resin. Not only can (II) be shaped into a shape almost similar to the shape of the mold, but also a product with good appearance can be obtained. Injection pressure is generally 40-140)cg/cd
Especially, 70 to 120 kg/clf is desirable.

FIG. 1 shows a side view of a typical mold used in injection molding to manufacture the dish-shaped article of the present invention. In FIG. 1, 1 and 1' are mounting plates for the mold, and 2 is a holding plate for a thin material. Further, 3 and 3' are hydraulic cylinders for operating a presser for thin-walled objects, and 4 and 4' are guide bins and support bins for holding plates for thin-walled objects. moreover,
5 is a rocket ring and 6 is a spray. Further, 7 is a thin material having a metal layer.

Note that it is important that the diameter of the gate is 6 to 30 mm. If the diameter of the gate is less than 6 mm, the fluidity of the resin deteriorates, and at the same time, as is clear from FIGS. 3 and 4, the root 1ean square
, hereinafter referred to as rrmsJ] also increases, and the gain rapidly decreases. On the other hand, if it exceeds 30+s, the concavity of the gate portion of the dish becomes large, which is not good in appearance.

Furthermore, by forming a foam layer inside the dish, surface precision is improved and the dents in the gate portion become less noticeable.

At this time, the foaming ratio is generally 1. O1 to 2.0 times, preferably 1.01 to 1.8 times, especially 1.0 times.
01 to 1.5 times is suitable. If the foaming ratio inside the dish-shaped object is less than 1.01 times, the dents in the gate portion will be noticeable and the improvement in surface precision will be poor. On the other hand, if it exceeds 2.0 times, there is concern that the surface rigidity will decrease or that the strength will be insufficient due to local defects.

Here, the expansion ratio is measured according to the Archimedes method (the same applies hereinafter).

As mentioned above, when applying paint to the surface of the metal layer of a plate-shaped object manufactured by the injection molding method, where the thermoplastic resin (I) and paint are not applied to the surface of the metal layer of the thin object, a special application method is required. There are methods that use a spray gun, a method using a brush wall, a method using a roll coaster, etc., but industrially, a method using a spray gun is used. The method of coating using a robot is particularly preferred because it is efficient.

FIG. 2 shows a partial cross-sectional view of a typical dish-shaped article obtained by the present invention. In Figure 2, A is a thermoplastic resin (1
) layer or coating layer, and B is a metal layer (metal foil). Further, D is a thermoplastic resin (II) layer or an inorganic filler-containing thermoplastic resin layer consisting of an inorganic filler and a thermoplastic resin (II).

Furthermore, D is a non-foamed layer, and D2 is a foamed layer.

Further, although C and C2 are included in the brimer layer, one or both may be absent.

According to the present invention, surface accuracy can be further improved than the invention described in the specification of Japanese Patent Application No. 1-9064.

Specifically, by using a foam layer inside the molded product, it is possible to obtain a dish-shaped product with even better surface precision.
We were able to produce a product that is extremely effective industrially. Although the technical reason is not clear, one possible reason is that residual stress is reduced by forming a foam layer.

[Examples or Comparative Examples] The present invention will be explained in more detail below using Examples.

In addition, the metal layer (metal foil) and thermoplastic resin (I) for producing the thin-walled products used in the examples and comparative examples
and paints and injection molded thermoplastics (II
) The types, physical properties, etc. of the thermoplastic resin (n) and inorganic filler for manufacturing are shown below.

[(A) Metal foil]

Aluminum, each approximately 20 doors thick [r
AgJ], copper and brass foils were used.

[(B) Thermoplastic resin (I)]

As a thermoplastic resin (1) with excellent weather resistance, the melt index (according to ASTM D-1238, constant n1 at a temperature of 250°C and a load of 10 kg) is 8.
．． Polyvinylidene fluoride [rP
VdFJ], a propylene homopolymer containing 0.4% by weight of a benzotriazole-based ultraviolet absorber and 0.5% by weight of carbon black [melt index [according to JIS K-7210, conditions are 14]. Measurement, hereafter referred to as rM I (1), J is 0.5 g
/10 minutes, hereinafter referred to as r P
．． High-density polyethylene containing 5% by weight of carbon black [density 0.958 g/Cl11. Melt index [Measured under conditions 4 according to JIS K-7210, hereinafter referred to as "M I (2) J" is 0.8 g/1
0 minutes, hereinafter referred to as rHDPE(1)J] as a mixture,
Acrylonitrile-styrene copolymer resin (acrylonitrile 23 parts by weight of a dibutyl tin malate stabilizer (manufactured by Sankyoki Gosei Co., Ltd., trade name: Stann BMI) and 2 parts by weight of dibutyl tin malate stabilizer (manufactured by Sankyoki Gosei Co., Ltd., trade name: Stann) were kneaded for 10 minutes using a roll (surface temperature 180°C). conduct,
The obtained composition [hereinafter referred to as rACSJ] and 20 parts by weight of dioctyl phthalate (as a plasticizer) and 5
．． 0 parts by weight of dibutyltin malate (dehydrochlorination prevention 11
A mixture of 100 parts by weight of vinyl chloride homopolymer (degree of polymerization 1100, hereinafter referred to as rPVcJ) was used.

[(C) Paint]

As paints, two-component fluororesin (manufactured by Dainippon Toyo Co., Ltd., trade name: V-Flon, hereinafter referred to as "F paint") and two-component polyurethane resin (manufactured by Nihon Yushi Co., Ltd., trade name: Hi-urethane, hereinafter referred to as "U paint") are used. ” was used.

[(D) Thermoplastic resin (■)]

(1) Olefin polymer As an olefin polymer, M I (1) is 2.0 g
/10 minutes of propylene homopolymer [hereinafter referred to as 1-P
P (B)J: l, M I (1) is 15g/
Propylene-ethylene block copolymer [
The ethylene content was 15% by weight, hereinafter referred to as "PP(C)J".

(2) Polycarbonate resin Medium-density polycarbonate resin produced using bisphenol A as the main raw material [density 1.2 g/cffl, MF 1 4.5 g/10 min,
Hereinafter referred to as rPCl] was used.

(3) Acrylonitrile-butadiene-styrene ternary copolymer resin (ABS resin) As the acrylonitrile-butadiene-styrene ternary copolymer resin, the ABS resin used in the examples and comparative examples of JP-A-58-134144 [rABSJ] ] was used.

(4) Acrylonitrile - Chlorinated polyethylene styrene terpolymer resin (AC3 resin) Acrylonitrile -
As a chlorinated polyethylene-styrene terpolymer resin,
A graft product [hereinafter referred to as rAcsJ] was produced in the same manner as ACS (1) used in the examples and comparative examples of JP-A No. 58-191751, and this ACS was
Similar to No.-191751, a dibutylmalate stabilizer was mixed and used.

Also, similar to the mixture (2) used in the Example of No. 58-191751, chlorinated polyethylene and acrylonitrile-styrene were used! The lfi resin and the stabilizer were mixed and the resulting mixture was used.

(5) Modified PPO (grafted product) Modified PPO produced as follows was used.

First, 2,6-xylenol was polycondensed by an oxidative coupling method to form poly 2,6-dimethylphenylene-1
．． 4-ether [intrinsic viscosity (measured in chloroform at 30°C, unit dl/g) 0.53, hereinafter referred to as "PPO"] was produced. 100 parts by weight of PPO, 25 parts by weight of styrene monomer, 10 parts by weight of styrene homopolymer [
The melt index (according to JIS K-6870, measured at a temperature of 2.16 cg and a load of 10 kg) was 13.0 g/10 minutes] and 2.1 parts by weight of di-tertiary-butyl peroxide. After mixing for 10 minutes using a Henschel mixer, a twin screw extruder (diameter 30 mm)
, resin temperature 270℃).
An O mixture [hereinafter referred to as "modified PP0J"] was produced.

[(E) Inorganic filler]

Talc (with an average particle size of 3Bn+) is used as an inorganic filler.
mica (aspect ratio approximately 8), glass fiber [single fiber diameter 11-, cut length 3 mm, hereinafter referred to as "GF"], and average particle diameter 0.8ZZ+1 Calcium carbonate [hereinafter referred to as r Ca CO3J] was used.

Experimental Examples 1 to 14 [(A) Production of various thin products] Molding thermoplastic resin (1) whose type is shown in Table 1,
Films were produced, each having a thickness of 100-.

In addition, on one side of the metal foil whose type is shown in Table 1, an acrylic brusher (manufactured by Showa Kobunshi Co., Ltd., trade name: Vinyroll) is applied.
92T) was applied to a thickness of 20 u# [Experimental Example 5゜8.9. and No. 16, a urethane-based brusher (manufactured by Toyo Morton Co., Ltd., trade name: Atcoat 335) was applied and then dried. Further, the urethane-based brimer was applied to the other surfaces to a thickness of 20 um and dried.

[(B) Thermoplastic resin (II) composition] Furthermore, 70 parts by weight of the thermoplastic resin (II) whose type is shown in Table 1 and 30 parts by weight of an inorganic filler (in Experimental Example 7, an inorganic filler was added) (without any agent) were tri-blended for 5 minutes using a Henschel mixer. Add each mixture obtained to the first
Pellets (compositions) were produced while kneading using a vented extruder under the conditions where the resin temperature is shown in the table.

[(C) Manufacture of plate-shaped object]

The metal foil (thin material) laminated with the thermoplastic resin (1) produced as described above is sandwiched in a mold, and insert injection molding is performed at the resin temperature shown in Table 1 to determine the thickness of the center part. Saga 6 dragon, peripheral thickness 3+om
A dish-shaped article having a major axis of 590 m+i and a minor axis of 510 mm was manufactured. At this time, the gate diameter of the molded product was varied from 4 to 30 mm. Note that a sandwich injection molding machine with a mold clamping force of 850 tons was used for this manufacturing. At this time, 0.2 to 0.7 parts by weight of azodicarbonamide was added as a foaming agent to 100 parts by weight of each thermoplastic resin.

In addition, in the column "Resin temperature" in Table 1, injection molding ■ indicates the resin temperature of the injection cylinder for forming the D1 layer shown in Figure 2, and injection molding ■ shows the resin temperature shown in Figure 2. The resin temperature of the injection cylinder for forming the D2 layer is shown.

In order to manufacture dish-like objects according to Experimental Example 5, the diameter of the gate was changed as shown in FIG. 3, and the rms of each dish-like object was measured. The results are shown in FIG. Also, Experimental Example 1. 2. 3.4. 5. 67, 8. 9.12
In order to manufacture a plate-shaped object using the method 14 and 14, the diameter of the gate was determined in the same manner as in Experimental Example 5, and the rms of each plate-shaped object was measured. In both cases, the same results as in Experimental Example 5 were obtained.

Furthermore, in order to manufacture a dish-shaped article according to Experimental Example 10, the diameter of the gate was changed as shown in FIG. 4, and the rms of each was measured. The results are shown in FIG. Furthermore, Experimental Examples 11 and 15 were conducted in the same manner as Experimental Example 10. In both cases, the same results as in Experimental Example IO were obtained.

Note that the rms was measured using a three-dimensional coordinate measuring machine to measure each axis value of the design value based on the curved surface formula, and calculated using the following formula.

In this equation, Σ is the design value, and ΣA1 is l This is an actual measured value. Further, n is the number of measurement points (88 points).

Products with rms of 1.0 or less (dish-shaped products) have excellent gain;
Furthermore, when the dish-shaped object is used as a reflecting mirror for a parabolic antenna, it has good radio wave efficiency. Furthermore, as the diameter of the gate exceeds 30 m+s, the dent in the gate portion of the dish-shaped object becomes larger, which is not good in terms of appearance.

[Effects of the Invention] The dish-shaped product obtained by the method of the present invention exhibits the following effects (characteristics) including its manufacturing process.

(1) It is possible to obtain products with unprecedented high surface precision.

(2) Surface accuracy can be easily improved by changing the diameter of the gate.

(3) The dish-shaped object is lighter than one made of metal.

(4) Thin products are easy to handle, for example, they can be stored in rolls, and they can be continuously supplied to a mold during injection molding, which greatly improves productivity.

(5) Since the foam layer is formed inside the dish, the dents in the boss, ribs, and gate parts become less noticeable.

Since the dish-shaped object obtained by the method of the present invention exhibits the above-mentioned effects, it can be used, for example, as a parabolic antenna.

[Brief explanation of drawings]

FIG. 1 is a side view of a typical mold used in injection molding to produce a dish-shaped article according to the method of the present invention. Moreover, FIG. 2 is a partial sectional view of a typical dish-shaped article obtained by the method of the present invention. Furthermore, FIGS. 3 and 4 show the gate diameter (horizontal axis) and rms of Experimental Example 5 and Experimental Example 10.
(vertical axis). 1 and 1'...Mold mounting plate 2...Holder plate for thin-walled objects 3 and 3'...Hydraulic cylinder for actuating presser for thin-walled objects 4 and 4'...Guide pin and presser for thin-walled objects Plate support 5...Rocket ring 6...Spray 7...
・Thin material A having a metal layer...Thermoplastic resin (I) layer or coating layer B...Metal layers C and C2...Primer layer D...Thermoplastic resin (II) layer or inorganic filling Agent-containing thermoplastic resin (II) layer Dl...non-foamed layer D2...foamed layer

Claims (1)

[Claims] When manufacturing a thermoplastic resin plate-shaped article laminated with a thin-walled article having at least a metal layer on its surface by insert injection molding, the cross-section of the plate-shaped article is defined by a parabola, and the surface of the plate-shaped article is defined by the parabola. In molding a dish-shaped object whose continuous line is expressed by a general curved surface formula, the gate diameter is set to 6 to 3.
A method for manufacturing a dish-shaped article, characterized in that the foam layer is formed only inside the dish-shaped article.